There is a clear need for a low cost, network manageable, advanced gas sensor for sulfur hexafluoride gas (SF6) used in high voltage electric switchgear. SF6 plays a crucial arc-suppression role in this equipment. An expensive commodity and a potent greenhouse gas (GWP 23,900 times that of CO2), SF6 lost through leakage is a costly problem justifying an effective monitoring system. The instant invention appreciates the application requirements and the sensor and communications network technologies required to meet them. The invention further supports security aspects that are paramount and tolerates the outdoor substation application environment which is challenging.
Worldwide, of 7 million kg of SF6 produced annually, most (˜75% or 5.5 metric tones per annum) is used for electric power equipment. Consequences for the environment and cost implications for electrical energy producers and users are clearly conveyed. Lower-impact, lower-cost alternatives to SF6, though sought, are not found. Techniques for estimating emissions have been based predominately upon indirect, mass-balance accounting methods that are costly and error-prone. Trials using expensive equipment (e.g. IR camera) combined with substantial labor have nonetheless shown that environmental impacts and gas expense arising from leakage are significant and can be reduced.
Presently, SF6 contributes 3% CO2-equivalent emissions. As global electric usage (3×106 Wh/capita) ascends to U.S. levels (1.3×107 Wh/capita), global generation increases 5-fold. While CO2 emission per kWh generated must surely decrease, SF6 emissions will scale with distribution. Switchgear equipment manufacturers and utilities need a low cost, network manageable, advanced gas sensor to achieve reductions in SF6 emissions per kWh.
All electric producers and users benefit. The instant invention targets economical, distributed sensor technology that can be applied worldwide to achieve a 100-fold reduction in emissions rate—a tremendous opportunity for the environment and economies worldwide.